Thermo-electric cooler for use in an optical assembly

Abstract

Optical assemblies of the type supported on an optical bench and comprising a one or more components such as lasers, lenses, filters, isolators and waveguides, are sensitive to movement variation. One of the causes of movement is temperature tracking. Previously, thermo-electric coolers have been used to maintain the top-surface temperature of an optical bench within a certain range. However, although thermo-electric coolers are operable to maintain optical bench temperature they are themselves still sensitive to temperature tracking and can deform. Because an optical bench is typically supported on the top surface of a thermo-electric cooler this leads to deformation of the optical bench itself and as a result performance of the optical assembly is affected. An improved design of thermo-electric cooler is described where the top surface of the cooler is divided into separate regions, each having a neutral region in which deformation is minimal. A thermally conductive sheet is placed over each of these regions such that only one temperature monitor is required. Optical components are then supported over the thermally conductive sheet in the neutral regions.

Description

The present invention relates to a thermo-electric cooler for use in an optical assembly.BACKGROUND TO THE INVENTIONOptical assemblies of the type supported on an optical bench and comprising one or more components such as lasers, lenses, filters, isolators and waveguides, are sensitive to movement variation. One of the causes of movement is temperature tracking. The term, "temperature tracking" is used to refer to a temperature dependent variation in the output signal of an optical assembly as a direct result of the movement of components in the optical assembly due to thermal expansion and contraction. This problem is particularly severe for optical assemblies in which the length of the "optical train" is significant; for example, where there are a plurality of optical components positioned in series along the optical bench.An aim of the present invention is therefore to minimise the impact of temperature tracking for optical assemblies.Previously, thermo-electric coolers have bee...

AI Technical Summary

Benefits of technology

This provides the advantage that each region of the surface has a "neutral region" in which deformation as a result of temperature variation is minimal. By dividing the surface into regions, more of these "neutral regions" are available.

Preferably the regions in the surface are of substantially the same size and shape. This provides the advantage that the "neutral regions" of each region of the surface behave in substantially the same manner.

Preferably the thermally conductive layer is arranged to protrude into each of the gaps. This is advantageous because more "slack" is provided in the thermally conductive layer which can be used when substantial deformation of the top surface of the thermo-electric cooler occurs.

Problems solved by technology

This problem is particularly severe for optical assemblies in which the length of the "optical train" is significant; for example, where there are a plurality of optical components positioned in series along the optical bench.

However, although thermo-electric coolers are operable to maintain optical bench temperature they are themselves still sensitive to temperature tracking.

Because an optical bench is typically supported on the top surface of a thermo-electric cooler this leads to deformation of the optical bench itself and as a result performance of the optical assembly is affected.

However, this method does not actually prevent deformation from occurring it merely works to minimise the resulting effects.

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